The present invention relates to an envelope indexing head and to an indexing apparatus which is equipped with the same.
Automation of postal sorting operations has necessitated the prior indexing of envelopes, that is, the printing of marks on the envelopes which correspond to the address elements written in clear form. These marks must then be automatically read by the sorting machines.
At the present time, these marks are provided by printing in actinic ink a number of vertical strokes along a horizontal line which is about 50 mm in length and known as the indexing line. These strokes are about 4 mm in height, 0.4 mm in width and their "pitch" is about 1.66 mm. In the current indexing machine code, there are 30 vertical stroke places. The presence or absence of strokes, in other words, their number and distribution along the indexing line is characteristic of a predetermined indexing according to the code employed. It is this sequence of strokes along the indexing line which is read by the automatic sorting machine. This reading requires that the indexing line is located with some precision both with respect to the bottom of the envelope and with respect to its front portion.
The indexing operations comprise reading the address, translating the same into a control language, the transmitting of the control signals thus determined to the indexing head together with the signal to print.
The indexing head is the device which prints the indexing strokes on the envelope when it receives the control signals characteristic of the indexing marks to be printed.
The processing of these control signals as a result of reading the address is effected either automatically or manually by an operator. In the latter case, the operator taps on a keyboard the information read on the address and a logic device which is not part of the present invention translates the information tapped on the keyboard into a program for supplying the various circuits of the indexing head according to the machine code employed. The printing operation is triggered by the transmission of an execution signal by the logic device which supplies the various circuits of the indexing head in accordance with the program which it has set up.